This invention relates to full bore ball valves for high pressure applications which are serviceable without removing the valve from the line. In another aspect, the invention relates to a particular method for fastening valve components having adjacent slidable surfaces wherein a channel is formed in the surfaces and an elongate flexible fastening member is inserted into the channel from outside of the valve, thereby preventing relative movement between the components. This particular fastening method allows substantial material savings due to the elimination of closure side bolting normally associated with ball valves, and reduced manufacturing costs because of the simplicity of the valve. In addition to material savings, the simplified valve design of the invention also provides higher seal integrity, simplified material traceability, and in-line serviceability.
In one general aspect of the invention, the ball valve comprises a housing having a tubular passageway to carry the fluid, a valve chamber located in the passageway to hold a generally spherical valve body having an axial bore located within the valve chamber, an opening in the valve housing to permit insertion and removal of valve components, and a removable bonnet to close said opening. A seal is retained by a pair of oppositely disposed, axially oriented cylindrical seats which are biased toward the valve body. This configuration is common to many types of ball valves, and is well known in the art. However, the particular fastener or retainer features of the invention, and combination of biasing means and retainer, are believed novel.
Applicant's search of the prior art revealed the following patents:
U.S. Pat. No. 2,629,615 PA1 U.S. Pat. No. 3,037,738 PA1 U.S. Pat. No. 3,171,429 PA1 U.S. Pat. No. 4,106,751 PA1 U.S. Pat. No. 1,738,450 PA1 U.S. Pat. No. Re. 23,041 PA1 U.S. Pat. No. 3,469,818 PA1 U.S. Pat. No. 3,765,645 PA1 U.S. Pat. No. 4,071,220
A number of ball valves have axial seats with adjustable seat pressure. For example, Jackson, U.S. Pat. No. 3,037,738 shows seats having external tapered screw adjustments, as well as internal adjustments of seat pressure both with and without biasing means. Paul, U.S. Pat. No. 3,765,645 discloses a ball valve serviceable through the bonnet wherein the seat pressure is adjustable with a single externally operated threaded wedge. In the Paul patent, bonnet closure is effected by a series of ball bearings located in aligned grooves in the bonnet and the body.
Iino, U.S. Pat. No. 4,071,220 shows an annular spring member which is fixed in the valve seal to urge the seats toward the ball. However, these spring members are not used as retainers, and are not accessible from outside of the valve. An externally removable ring-type retainer is shown in Niskin, U.S. Pat. No. 4,106,751; the ring slides around an annular groove between the casing and a removable internal retainer. The ring is not used in connection with a seat biasing member, but is simply a closure mechanism for the end of the valve. Other seat biasing means similar to the Jackson and Paul patents are shown in Ryan et al, U.S. Pat. No. 1,738,450, and Sturmer et al, U.S. Pat. No. 3,171,429. However, no disclosures of valves using the fastening mechanisms or seat biasing means of the invention are known to the inventor.
Accordingly, it is an object of the invention to provide a novel fastening mechanism to prevent relative movement between valve components having adjacent surfaces. More particularly, it is an object of the invention to provide a ball valve seat retainer which is removable through a port in the valve housing. In another aspect of the invention, a one piece, elongate flexible fastener is provided for rapid removal of the valve bonnet from the valve housing. It is yet another object of the invention to provide a combination of an externally accessible, flexible elongated fastener with a biasing means to provide a uniform, integral seal in a ball valve. These and other objects of the invention will be apparent from the following description of a preferred embodiment of the invention.